1. Field of the Invention
This invention relates to a process for removing sulfuric acid found in the product from a sulfoxidation process by extraction with concentrated hydrochloric acid.
2. Description of the Prior Art
In commonly assigned co-pending application, Ser. No. 40,740, filed May 26, 1970, there is disclosed and claimed a process for producing sulfonic acid without irradiation by reacting in a reactor substantially straight chain saturated liquid hydrocarbons with oxygen and sulfur dioxide under substantially anhydrous conditions in the presence of a low molecular weight acyl oxide such as acetic anhydride at temperatures of about 25.degree. to 55.degree.C. under pressures of from 0 to 100 psig while agitating throughout the process these reactants followed by continuously removing the resulting heavy phase containing product and unreacted paraffins from the reactor.
The linear sulfonate product prepared by this process contains about 35 mole percent of sulfuric acid. Although this quantity of sulfuric acid is high, it has no detrimental effect in a finished detergent formulation containing such sulfonates as the sodium sulfate formed from the sulfuric acid can be used as part of the "builders" in the detergent. Undesirably, it is not possible with this high a sulfuric acid content to obtain aqueous solutions of a neutral mixture at concentrations greater than 30% w/w owing to the separation of sodium sulfate at room temperature. Thus it would be advantageous with regards to increased facility in handling, improvement of minimum product value and appearance, if the sulfuric acid content could be reduced economically. Similarly, it would improve the economics of the process if the sulfuric acid could be made readily available for producing sulfur dioxide which could be used again in the sulfoxidation reaction.